To those familiar with the developing art of designing and constructing road-to-air crafts, the necessity for a collapsible wing system is obvious. One design for such collapsible wing system is the use of a telescoping aircraft wing in which a number of wing segments are used with more outboard segments being smaller than adjacent inboard wing segments such that the more outboard segments may be collapsed in a telescope fashion within a more inboard, neighboring, larger wing section.
Such a telescoping wing design is described in U.S. Pat. No. 4,824,053 to Branko Sarh. The '053 wing makes use of conventional metal rib forms where a metal skin is attached. Longitudinal spar segments associated with wing segments are tubular in shape and reduce in size the more outboard the spar is located. The assembly collapses in a telescopic manner.
In a telescoping wing assembly, wing segments must be securely locked into place once extended while maintaining rigidity in the deployed wing. In known telescoping wing assemblies, telescopically collapsible segments taper longitudinally to form conical shapes. Thus, when segments are extended telescopically, the broader bases of an internal, extending section come into contact with the narrower tops of the encompassing section and, due to the interference, are prevented from further extension. Accordingly, the wing segments are locked into the extended position due to contact inference between portions of neighboring segments.
While this achieves the goal of rigidity, there is a tendency for segments to stick or jam together so that the systems are prone to retraction failure. In any regard, in such systems great tensile force is necessary to collapse the assembly. This creates operational hazards when not accomplished smoothly. In addition, the need of custom fitting the collapsible segments increases the cost of segment fabrication and the interactions of the segments during extension and collapse leads to short lives of material at the zone of section contact.